My invention relates to data transfer apparatus employing magnetic disks as data storage media, and more specifically to such apparatus of the kind known as a Winchester drive wherein a magnetic disk is fixed to a drive spindle and is normally held in contact with a transducer head, the latter moving out of contact with the disk upon rotation thereof for data transfer. My invention is also specifically directed to a method of operation for such magnetic data transfer apparatus.
In a Winchester disk drive, as is well known, a rigid magnetic disk or disks and an associated transducer head or heads are semipermanently enclosed in a dustproof housing for data transfer in a dustfree environment. The disk or disks are firmly mounted on a drive spindle, and the head or heads are biased into contact with the disk or disks when the latter are out of rotation. When the disk or disks are set into rotation and pick up speed to, say, 1500 revolutions per minute (rpm), streams of air created thereby cause the head or heads to move out of contact therewith. The head or heads transfer data to or from the revolving disk or disks while being thus spaced, normally from 0.4 to 0.5 microns, therefrom.
The Winchester drives as so far constructed as above have been susceptible to shocks or vibrations as the transducer head or heads are normally in contact with the magnetic disk or disks. At the time of shipment, therefore, the Winchester drives have had to be enclosed in shockproof packages. The added costs for such packaging and shipping of the Winchester drives have not been negligible for their manufacturers and dealers and, in consequence, for their purchasers. After being unpackaged, too, the Winchester drives have demanded careful handling so as not to give damage to the contacting disks and heads.
A problem has also existed in the operation of the Winchester drives. When the disk or disks are set into rotation for data transfer, the head or heads slide thereover until they pneumatically move apart therefrom upon increase in the revolving speed of the disk or disks to 1500 rpm or so. Such sliding of the head or heads over the disk or disks also takes place when the revolving speed of the disk or disks falls below 1500 rpm upon completion of the data transfer. There has been a high likelihood of the head or heads destroying the data storage tracks of the disk or disks while thus sliding thereover at the start and end of each run of data transfer.